textproduct: Quad Cities

KEY MESSAGES

- A storm system passing through the Upper Midwest Tuesday evening into Wednesday will bring widespread showers and storms to the area. There will be a low-end risk for strong- severe storms, with heavy rainfall accompanying storms.

- Quiet weather Thursday into Friday, as high pressure passes overhead. Seasonal conditions will remain, with mostly clear skies.

- Another stretch of potentially active weather this weekend into the next work week, bringing daily chances of precipitation for some.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 214 PM CDT Mon Sep 7 2026

Weak upper ridge will start to break down overhead tonight, with surface high pressure over the Great Lakes Region getting shunted east. As this pushes east, llvl southwesterly flow increases overhead in response to a shortwave trof digging into the north- central CONUS. Overnight tonight, plenty of llvl dry air will remain, with increasing mid-high clouds resulting from this return flow. Overall dry conditions will remain through the night, with temperatures in the 60s and a light breeze.

Tuesday into Tuesday night, we will start to see a stronger response from the increasing warm advection overhead, especially later in the day. Prior, we will see temperatures increase well above seasonal norms once again. Areas along and south of Interstate 80 will near 90s degrees, if not reach the low 90s, with areas north in the mid- upper 80s. Fortunately, the better moisture will not move in until late in the day, which should largely keep heat indices below 100 through the afternoon. Areas south of Interstate 80 in Eastern Iowa will have the better chance of seeing heat indices approaching the mid-upper 90s. So, even though we might not be oppressively hot like last week, we will still be quite warm tomorrow. Later Tuesday afternoon and through the evening, the LLJ will increase to near 25- 35+ KTs. This will increase moisture quite a bit, pooling along/ahead of a cold front approaching from the northwest overnight. This increase in moisture will result in PWATs nearing 2.00"+. Thus, with plenty of moisture in place and sufficient upper/lower level forcing moving in, widespread showers and storms are likely Tuesday evening into Wednesday.

There will be a low-end severe threat with these storms, but confidence remains low. Short term guidance favors meager instability (<1000 CAPE) with deep layer shear around 30 KTs. Thus, while an organized storm cannot be ruled out, the threat for a strong to severe storm should be relatively isolated. The primary threat with any strong-severe storm will be damaging wind gusts, largely influenced by precipitation loading in the thunderstorms. Secondary threat would be hail, but confidence in this occurring is low at this time. Another expected impact from these storms is heavy rainfall. The increasing jet overnight will converge into the approaching cold front, where we will also see streams of vorticity ahead of the main wave providing forcing for rounds of potential showers/storms. Widespread rainfall can be expected in eastern Iowa, with lesser coverage east of the Mississippi River. Some areas may see repeated rounds of showers/storms through the night, where localized areas may see 1.00-2.00" of rain. Given the recently dry and hot conditions, soils should have capacity for much of this to easily infiltrate the ground. Although, with PWATs around 2.00"+ (well above seasonal norms), quick and efficient rainfall accumulation is possible in areas. Thus, a localized flash flood threat cannot be ruled out, especially for eastern Iowa. As such, the WPC has highlighted these areas in a Slight Risk, level 2/5, for Excessive Rainfall.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Issued at 214 PM CDT Mon Sep 7 2026

Cold front isn't expected to be out of our area until early afternoon on Wednesday, which will keep precipitation chances over much of the area through the first half of the day. We will see shower/storm coverage decrease from northwest to southeast through the morning, with best chances for precipitation in the afternoon hours for areas in western Illinois and northeastern Missouri. At this time, we are not expecting much in the way of strong-severe storms. Much of the remaining instability will have been worked through, leaving us with a shield of stratiform rain and little/no embedded thunder. Otherwise, we will see mostly cloudy conditions through the day, with temperatures in the low 80s and light west to northwest winds.

Thursday into Friday, upper level flow becomes more northwesterly as a weak wave passes through and weak ridging builds over the Central CONUS. This wave will be through our area by midday Thursday, with surface high pressure moving in behind. A brief period of quiet and seasonal weather will result, with mostly clear skies and temperatures around 80 on Thursday into Friday. Overnight temperatures will cool off a bit compared to recent nights, with most in the mid 50s. Friday, the weak ridge will pass east of the area, with southwesterly flow increasing ahead of a quickly- approaching shortwave trof. This wave is due to come through Friday night into Saturday, prompting our next chance of precipitation (30- 60% chances). Showers and storms will be possible along the associated cold front, but accumulations should be on the lower-end due to the quick movement of this wave. There remains some uncertainty, owing to moisture availability.

Saturday and beyond appear to be a continuation of potentially active weather, with us falling largely under upper level zonal to southwesterly flow. This patten would favor us falling under the path of passing shortwaves through the weekend and into next week. Thus, daily PoPs (20-40%+) are in the forecast through this stretch, with temperatures remaining above seasonal norms.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1231 PM CDT Mon Sep 7 2026

VFR conditions will prevail through the TAF period, with surface high pressure over the Great Lakes Region ushering weak southeasterly flow into the area. Mostly clear skies this afternoon will give way to increasing mid-high clouds tonight. No sig wx is expected at this time.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.